GHRP Peptide: Growth Hormone Releasing Peptides

What is a GHRP peptide?

A GHRP peptide is a short chain of amino acids, built in a laboratory, that copies the signal the body's own hunger hormone sends when it tells the pituitary gland to let growth hormone out.

These are small molecules. The 1993 paper that first reported three of them in people described the group as peptides of six to seven amino acids that release growth hormone in animals and in humans, and the shortest member found later is only five. Two reviews, one from 2017 and one from 2026, name the same members, and the table below lists them.

One point gets lost often. The name says what these peptides do, not where they come from. Growth hormone releasing hormone is a signal the body makes; a growth hormone releasing peptide is not. Every GHRP is a synthetic compound, and the 2017 review calls them pioneer synthetic, non-natural peptides for that reason. The glossary entry for GHRP carries the one-line version.

Sources: Bowers 1993, J Pediatr Endocrinol, PMID 8374685; Berlanga-Acosta et al. 2017, Clin Med Insights Cardiol, PMC5392015; Dominikowski et al. 2026, Front Endocrinol, PMC13322892.

How do GHRPs act on the ghrelin receptor?

A GHRP binds the ghrelin receptor, known as GHS-R1a, and that binding asks the pituitary for a burst of growth hormone rather than supplying any hormone itself.

The receptor sits in two places that matter here: on the pituitary gland, and in the hypothalamus above it. The team that cloned the receptor in 1996 wrote that these small secretagogues act at both sites to stimulate and amplify pulsatile growth hormone release. Pulsatile is the useful word. Growth hormone normally leaves the gland in bursts, and a GHRP works on the switch that times them, so the gland and its own feedback signals still set the ceiling.

There is a second route to the same gland, through the growth hormone releasing hormone receptor, and the compounds that take it are a different family. We keep that comparison in one place instead of repeating it: what is a peptide secretagogue sets the two receptor families side by side, and growth hormone peptides explained walks through the axis as a whole.

Sources: Howard et al. 1996, Science, PMID 8688086; Berlanga-Acosta et al. 2017, PMC5392015.

Why did GHRPs exist before ghrelin was found?

Because chemists built them first. The synthetic peptides came before anyone knew the natural hormone they imitate existed, and they are what led researchers to it.

The 2017 historical review tells the order plainly. Cyril Bowers noticed that chemical relatives of a small natural molecule, enkephalin amide, made pituitary cells release growth hormone. His group published the first of the class in 1984: a six amino acid peptide, later called GHRP-6, reported as specifically releasing growth hormone in cells and in animals. A seven amino acid peptide, GHRP-1, followed, then two more six amino acid peptides, GHRP-2 and hexarelin.

The receptor arrived next. In 1996 a research team cloned the receptor these compounds act on and said openly that its natural ligand was unknown, and that the secretagogues appeared to imitate a hormone nobody had discovered. That hormone turned up in 1999: ghrelin, a peptide of 28 amino acids purified from the stomach. So the order ran lab peptide, then receptor, then hormone, which is the reverse of how a drug class usually begins.

Sources: Bowers et al. 1984, Endocrinology, PMID 6714155; Howard et al. 1996, Science, PMID 8688086; Kojima et al. 1999, Nature, PMID 10604470; Berlanga-Acosta et al. 2017, PMC5392015.

The GHRP family, side by side

Here are the members the two reviews name, with how long each peptide is, the year it first appeared in a published study, where it stands with US regulators, and our page on it.

Two notes on the table. GHRP-1 and GHRP-2 read "by 1993" because the paper reporting both in human work does not say when either was made, and a date we can prove beats one we guess. The status column is a check we ran: on 5 November 2026 a Drugs@FDA search for each name returned no approved product, while the same search returns records for approved peptide drugs.

Two members are often read against each other, and those comparisons have their own pages: GHRP-2 versus GHRP-6, ipamorelin versus GHRP-6 and hexarelin versus ipamorelin.

Sources: Bowers et al. 1984, PMID 6714155; Bowers 1993, PMID 8374685; Ghigo et al. 1994, J Clin Endocrinol Metab, PMID 8126144; Raun et al. 1998, Eur J Endocrinol, PMID 9849822; Drugs@FDA, searched 5 November 2026; FDA, bulk substances that may present significant safety risks.

What do studies report about effects and side effects?

Published research reports a rise in growth hormone and, for several members, a rise in appetite. It does not establish that any of this changes a person's body, and the older members move hormones other than the one they were designed for.

On the first half of that: the 2026 review states that direct evidence for meaningful changes in body composition outcomes in humans remains limited and should be interpreted cautiously, and that the appetite response is the clearest extra effect the class shows. That is the honest answer, and no figure here will tell you otherwise.

On the second half: in the study that introduced ipamorelin, both GHRP-6 and GHRP-2 raised ACTH and cortisol in swine, while ipamorelin did not move them beyond what the natural releasing hormone did, which is where its reputation for selectivity comes from. Human studies of hexarelin report rises in prolactin and in the cortisol axis as well. Regulators add their own note. The FDA lists GHRP-2, GHRP-6 and ipamorelin acetate among bulk substances for compounding that may present significant safety risks, naming concerns such as immunogenicity. For GHRP-2 it also records reports of serious adverse events in patients who received it, while saying the cause was not established. The 2026 review adds that growth hormone secretagogues sit on the World Anti-Doping Agency prohibited list.

What we will not print: an amount, a schedule, or any suggestion that a person take one of these. The research record is what this page carries.

Sources: Raun et al. 1998, PMID 9849822; Dominikowski et al. 2026, PMC13322892; Berlanga-Acosta et al. 2017, PMC5392015; FDA, bulk substances that may present significant safety risks.

Where a GHRP shows up in our published lab results

One item in our catalog contains a peptide of this class: ipamorelin, blended with the growth hormone releasing hormone analog CJC-1295. Its batch certificate is published, so the figures here are the ones on that document.

An independent third-party lab tested lot CJI-260413-A in June 2026 and reported 98.60 percent purity, 10.05 mg of net peptide content and identity confirmed by HPLC + LC-MS (per component), on certificate COA-2026-3168. We walk through how to read a certificate of analysis line by line. Every released batch certificate is on our certificates page, and the blend itself has its own compound page.